Back-cross reciprocal monosomic analysis of Fusarium head blight resistance in wheat (Triticum aestivum L.)

Fusarium head blight (FHB or scab) caused by Fusarium spp. is a widespread disease of cereals causing yield and quality losses and contaminating cerea l products with mycotoxins. The breeding of resistant varieties is the meth od of choice for controlling the disease. Unfortunately, the genetic basis of scab resistance is still poorly understood. We present the results of a back-cross reciprocal monosomic analysis of FHB resistance using the highly resistant Hungarian winter wheat line 'U-136.1' and the highly susceptible cultivar 'Hobbit-sib'. Resistance testing was performed in a held trial ar tificially inoculated with a Fusarium culmorum conidial suspension. Five he mizygous families containing 'U-136.1' chromosomes 6B, 5A, 6D, 1B, and 4B h ad a visually reduced spread of infection compared to lines having the 'Hob bit-sib' chromosome. Chromosome 2B from 'U-136.1' had an increased spread o f infection. The critical chromosomes controlling seed weight were 6D, 3B, 5A, and 6B while those controlling deoxynivalenol (DON) content were homoeo logous groups 2 and 6, although the latter effects were not significant due to a high coefficient of variation. Results from this and other studies sh ow that chromosomes 6D, 6B, 5A, 4D, and 7A have frequently been associated with scab resistance in a number of wheat cultivars. Research groups now at tempting to map scab resistance in wheat using markers should pay special a ttention to the above-mentioned chromosomes.